Semaglutide

The GLP-1 drug that started the modern weight-loss era: Ozempic and Wegovy.

FDA-approved (Ozempic 2017, Wegovy 2021)Evidence

Overview

Semaglutide is a GLP-1 receptor agonist made by Novo Nordisk. It is FDA-approved as Ozempic (type 2 diabetes), Wegovy (weight management and cardiovascular risk reduction), and Rybelsus and the Wegovy pill (oral forms). It has one of the largest evidence bases of any weight-loss drug, including a major heart-outcomes trial.

How it works

A modified version of the natural hormone GLP-1 with a fatty-acid side chain that binds albumin, stretching its half-life to about a week. It lowers appetite through the brain, slows stomach emptying, and increases insulin release when blood sugar is high.

Evidence

5/5

FDA-approved with large RCT programs (SUSTAIN, STEP, SELECT). SELECT showed a 20% reduction in major cardiovascular events in people with heart disease and overweight.

Half-life

About 7 days (once-weekly dosing)

Known as

Ozempic, Wegovy, Rybelsus, NN9535, AMP-1 (SM)

Compound facts

Type: GLP-1 receptor agonist (incretin analog)
CAS Number: 910463-68-2
Molecular Formula: C187H291N45O59
Molecular Weight: 4113.58 g/mol
Amino Acids: 31 (backbone)
Half-Life: ~165 hours (once-weekly)

Reported benefits

Human data

Weight loss

STEP-1: about −15% average weight loss at 68 weeks on 2.4 mg vs about −2% on placebo.

Human data

Fewer heart attacks and strokes

SELECT trial: 20% lower risk of major cardiovascular events in adults with heart disease and overweight.

Human data

Blood sugar control

Strong A1c reductions in type 2 diabetes (SUSTAIN trials).

Human data

Higher-dose option

A 7.2 mg weekly dose (Wegovy HD) gave about −21% at 72 weeks in the STEP UP trials.

“Anecdotal” means reported by users, not shown in controlled trials.

Community-reported regimens

Not recommendations. These are commonly cited ranges, shown so you can see what real-world use looks like.

Plan	Dose	Frequency	Duration	Route
Wegovy label start Label titration: 0.25 → 0.5 → 1 → 1.7 → 2.4 mg, stepping up every 4 weeks.	250 mcg	Once weekly	4 weeks	Subcutaneous (abdomen, thigh, upper arm)
Ozempic step 2 Ozempic (diabetes) goes 0.25 → 0.5 → 1 → 2 mg.	500 mcg	Once weekly	At least 4 weeks	Subcutaneous
Wegovy maintenance Standard weight-management maintenance dose after about 16 weeks of titration.	2400 mcg	Once weekly	Ongoing	Subcutaneous

Reconstitution calculator

Set up for Semaglutide. Switch peptide or vial size any time.

Peptide

Vial

Walk me through it

1Mix

Add 2 mL water for 5 mg/mL

2Draw

Draw to 5 units = 0.05 mL = 250 mcg

Drag the plunger to set your dose.

3Inject

Next site

Right belly, upper

Tap a site after you inject to keep a rotation.

Pinch the skin, stay 2 in. from the navel, then into a sharps bin.

Peptide in vial (mg)

Water to add (mL)

Dose

Doses per day

Days per week

Community doses:

Doses per vial: 40
Vial lasts: 280 days
Good once mixed: ~28 days
Syringe: 30-unit, 0.3 mL

The vial outlasts its ~28-day shelf life once mixed. A smaller vial wastes less.

Easier numbers, add this much water:

Math only: concentration (mg/mL) = vial mg ÷ mL of water; units = dose (mg) ÷ concentration × 100. Always double-check against your own vial label and a clinician. This tool does not recommend a dose.

Reconstitution

Diluent: Bacteriostatic water (0.9% benzyl alcohol) — allows multiple draws from one vial.

Wipe both vial tops with an alcohol swab and let dry.
Draw the diluent, then inject it slowly down the inside wall of the vial — never straight onto the powder.
Swirl gently or let it sit; do not shake. Foam can damage peptides.
Solution should be clear. Cloudy, stringy or discolored = discard.
Early doses are tiny. A more dilute mix makes small doses easier to measure accurately.
Common mix: 10 mg + 4 mL = 2.5 mg/mL (250 mcg = 10 units).

Full reconstitution guide →

Storage

Powder

Freezer / fridge

Keep sealed vial in the freezer (−20 °C) for long-term storage; fridge (2–8 °C) is fine for a few weeks. Keep dry and out of light.

After mixing

~28 days

Refrigerate at 2–8 °C. Never freeze after mixing. Keep upright, capped, and out of light.

Travel

Keep cool

Short trips at room temperature are generally fine for powder; keep mixed vials cold.

Branded pens have their own storage rules; these notes apply to powder vials only.

Side effects & cautions

Reported side effects

Nausea, vomiting, diarrhea, constipation (most common, worst during dose increases)
Belly pain, bloating, burping
Fatigue, headache
Injection-site reactions
Diabetic eye (retinopathy) complications reported in people with type 2 diabetes

Cautions

Boxed warning class: GLP-1 drugs caused thyroid C-cell tumors in rodents. Do not use with a personal or family history of medullary thyroid cancer or MEN2.
Pancreatitis has been reported. Severe, persistent belly pain that may spread to the back needs urgent care.
Gallbladder problems (gallstones) are more common, especially with fast weight loss.
Do not combine with another GLP-1 drug (semaglutide, tirzepatide, retatrutide, etc.).
Raises low-blood-sugar risk when combined with insulin or sulfonylureas.
Not for use in pregnancy; stop well before trying to conceive. Slowed stomach emptying can matter before surgery or sedation.

FDA & international status

FDA

FDA-approved (Ozempic 2017, Wegovy 2021)

Approved for type 2 diabetes (Ozempic, Rybelsus), chronic weight management and cardiovascular risk reduction (Wegovy injection and, since late 2025, the Wegovy pill). The FDA declared the semaglutide shortage over in February 2025, and enforcement discretion for compounding ended later in 2025. Research vials are not the approved drug.

European UnionAuthorised as Ozempic, Rybelsus and Wegovy (including a 7.2 mg Wegovy dose).

United KingdomLicensed as Ozempic, Rybelsus and Wegovy; MHRA approved doses up to 7.2 mg for obesity.

CanadaApproved as Ozempic, Rybelsus and Wegovy.

AustraliaApproved as Ozempic and Wegovy (prescription only).

WADANot prohibited; on WADA's Monitoring Program since 2024.

Regulations change often — verify with the FDA, EMA, MHRA, Health Canada, TGA and WADA before acting.

Often paired with

Cagrilintide

This pairing is Novo Nordisk's CagriSema, tested in phase 3 (REDEFINE) and under FDA review. Research-vial combining is not the same as the studied fixed-dose product.

Where to buy

Size	Price	Per mg	Stock	Latest COA
10 mg	$49.99	$5.00	In stock	99.17% pure, lot SEM0001 ILS Labs, tested 2026-08-03

Amino Club list prices as of 2026-10-07, before promo codes. Multi-buy: 2+ units 5% off, 3+ units 7.5% off, 10+ units 40% off. Prices change; confirm on the product page. Mixing? Their bacteriostatic water is Amino H2O from $19.99.

Semaglutide at Amino Club

Check sizes, current price and the certificate of analysis (COA) on the product page. Sold for in-vitro research only.

Shop Semaglutide ↗

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Look for a batch-specific COA with HPLC purity (≥98%) and mass-spec identity.
Typical vial sizes: 10 mg.

FAQ

Ozempic vs Wegovy: what's the difference?

Same molecule. Ozempic is labelled for diabetes (up to 2 mg); Wegovy is labelled for weight management (2.4 mg, or 7.2 mg in some regions).

Do I regain weight if I stop?

Usually some. In the STEP-1 extension, people regained about two-thirds of the lost weight within a year of stopping.

Why is my 0.25 mg dose only 10 units?

At 2.5 mg/mL, 0.25 mg is 0.1 mL, which is 10 units on a U-100 insulin syringe. Doses grow as you titrate.

Read the primary research on PubMed ↗